1. Field of the Invention
The present invention relates to a support mechanism for supporting thereon a set of upper and lower forming dies to be opened and closed in a forming process of synthetic resin products such instrument panels, safety pads or the like for use in automotive vehicles.
2. Description of the Prior Art
Disclosed in Japanese Patent Publication No. 3-4013 is a support mechanism for a set of upper and lower forming dies which includes a base structure for fixedly mounting thereon the lower forming die, a pair of opposed upright side plates fixed to the base structure in parallel to one another and arranged at each side of the lower forming die, and a movable support frame disposed between the side plates and located above the lower forming die for supporting thereon the upper forming die. The side plates each are provided with a guide slot along which a guide rail in the form of a rack bar is attached, and the movable support frame is provided thereon with an electric motor and with a lateral drive shaft which is slidably engaged at its opposite ends with the guide slots of the opposed side plates. The movable support frame is further provided with a pair of guide rods secured to its opposite sides and slidably engaged with the respective guide slots of the side plates. The drive shall is provided thereon with a pair of axially spaced pinions which are in meshing engagement with the respective guide rails on the side plates. The electric motor is drivingly connected to the drive shaft through a reduction mechanism. In operation, the drive torque of the electric motor is transmitted to the drive shaft through the reduction mechanism, and in turn, the pinions are driven to rotate along the guide rails so that the movable support frame is moved upward along the guide rail is to separate the upper forming die from the lower forming die and open it for entry of an article to be molded into the lower forming die.
In the support mechanism described above, however, the electric motor and associated torque transmission parts are mounted on the movable support frame. With such arrangement of the component parts, the support mechanism becomes high and large in size, and the upper forming die is positioned apart from the operator when it has been opened. This results in difficulty for the operator in setting an article to be formed. Additionally, the movable support frame becomes heavy, resulting in an increase of the power for operation of the support mechanism and a slowdown of operation speed of tile same.